Frank j



(No Model.)

I. J.- SPRAGUE.

ELECTRO DYNAMIC MOTOR.

Patented Mar. 10, 1885 0 0 61 6 cud a6 Jags. 1719.4 1 7155 W6 UNITEDSTATES PATENT @rrrcn.

FRANK J. SPRAGUE, OF NEIV YORK, N. Y.

ELECTRO-DYNAMIQ MOTOR.

EiPECIPICATION forming part of Letters Patent No. 313,546, dated March10, 1885.

Application 'filed November 4, 1884.

' New York, in the county and State of New York, have invented a certainnew and useful Improvement in Electro-Dynamic Motors, of which thefollowing is a specification.

In an application for Letters Patent filed February 20, 1884, of whichthis application is a division, I have set forth a method of regulatingthe speed and power of electro-dynamic motors by the inverse varying ofthe magnetizing effect of the field-magnet coils of the motor.

The present application relates to the construction and apparatus setforth in the prior one just referred to, but which were not claimedtherein, the claims being confined to the method of operation alone.\Vhile the invention herein set forth was designed espe cially for theregulation of motors, it is adapted as well to the regulation ofdynamo-electric generators by varying the magnetizing effect of theirfield-coils.

In carrying out my invention, I wind the field-magnet of amachinepreferably a shunt wound motor-in sections of coils, and makeconnections therefrom to a suitable commutator in such manner that thesections may be progressively thrown into or out of multiplearc relationwith each other. By throwing a greater number of sections from a seriesrelation into multiple arc the magnetizing effect of the fieldcoils isincreased, the field is strengthened, and the mechanical effects in thearmature are reduced, as is set forth in the application above referredto. The armature being in shunt relation with the fieldcoils, thearmature-current is also incidentally effected by the change inresistance of the field. I may, however, employ other means for varyingthe armature-current, and, preferably, those set forth in my Patent No.295,454, dated March 18, 1884. Here the relation between thefield-sections in series and those in shunt relation to the armature isvaried. In that patent is set forth a method of field regulation by theuse of adjustable independent fieldcoils; but I prefer the method hereinset forth.

To arrange the field-coils so that they may be changed from series tomultiple arc with each other, I prefer to have the sections divided intotwo sets orv ranges, each connected (X0 model.)

with the supplying-circuit at one end and having the other free. Byconnecting the free end of each range to different points of theopposite range, more or less of the coils are placed in parallelcircuit. If I employ together with this regulation thearmature-regulation just referred to, the same coummutator may be usedfor both purposes. The field regulation or regulation of both field andarmature maybe accomplished automatically by devices controlled byvariations in the speed of the motor. Thus a constant speed ismaintained.

The figures of the accompanying drawings are diagrams illustrative ofthe principles and features of my invention, and I will describe thesame in detail.

Figures 1 and 2 represent the arrangement set forth in the applicationreferred to.

O G are main conductorsj a a is the fieldcircuit, and a a a thearmature-shunt. In Fig. 2 the armature is shunted around a less numberof field-coils, the difference of potential atits circuit terminals islessened, and it receives less current, and the speed or power isdiminished.

The field regulation is illustrated in Figs. 3 and 4.. The fieldeoilsare broken at terminals 7) b, and by a suitable commutator, which willbe presently described, greater or less portions of the coils areprogressively thrown into multiple arc with each other, to decrease theresistance, strengthen the field, and diminish the speed, andprogressively removed from such relation to produce a contrary effect.In this arrangement the armature-terminals are considered as fixed;

Figs. 5 and 6 show the same arrangement of field, with the armaturecapable of being shunted around a greater or less number of thefield-coils, illustrating the fact that the,

present mode of regulation may be used in connection with that set forthin the application referred to. Incidentally the regulation of the fieldhas an increased effect, by the increase or diminution of the armaturecurrent due to the increase or diminution of the resistance around whichit is shunted; but by us ing the field and armature regulation togetheran enormous effect may be produced on the speed of the armature. By avery slight change'the racing of the armature, even if the whole load issuddenly thrown off, is prevented.

Fig. 7 illustrates the commutator and connections employed with the newmethod of regulating the field.

O O are the main conductors, and c, c, 0 &c., are sections offield-coils.

The commutator is composed of a circle of metal blocks (Z d d d, 850.,two of which are extended into the arcs e e. The connections from thefield-sections are made the first and last to single and opposite blocks(1 of the commutator, and each of the others to two blocks, d, d (1 andcl".

The pivoted commutator-arm consists of an insulating central portion, B,and metal extensions f f These ends each bear on one of the arcs andupon the range of contacts. The field-current from 0 passes to h, where(in the present position of the arm) it divides. part passing to contactd extension f, arc c, and coils 0, to the reuniting-point h. The restpasses through coils c to contacts (2, arc 6, extension f, and contactsd cl" to 72 It will be seen that coils c and c are thus placed inmultiple are to each other. By moving the commutator-arm in onedirection or the'other more or less of the sections of field-coils inwhich the magnet is wound are multiple-awed upon each other, and thestrength of the magnet is increased or diminished. Fig. 8 shows thisarrangement in connection with that for changing the relation betweenthe sections of field-coils in series and those in shunt relation to thearmature set forth in the patent referred to. Here the additional arms ZZ, insulated from each other, bearing on the contact-blocks and passingunder the arm B, are employed. The terminals of the armature M areconnected, respectively, with these arms. As the armsZ Z are moved, thearmature is shunted around a greater or less number of the field-coils,remaining in series with the remainder. The arms B and Z Z may worksimultaneously, if desired. By the use of the commutator shown in Fig.8, the armature current or the strength of the field, or both, may beregulated, the circuits never being broken, no adjustable resistancesbeing employed, and all the field-coils being constantly in circuit andproducing their magnetizing effect.

Fig. 9 illustrates an automatic arrangement which may be employed formoving the arm B to maintain a constant speed. A centrifu gal governor,F, is connected with the motorshaft, so as to be affected by variationsin speed. Its moving collar carries two contactarms, m m, insulated fromeach other, and connected, respectively, with the conductors O 0. Thesearms enter between the three armsnn a, which also are insulated from oneanother. G is a small electric motor one of whose terminals is connectedwith the two arms a n", the other with arm n. The motorshaft isconnected by a worm-gearing or other slowing-down gearing with the armB. The

connecting-spindle is for convenience ofillustration broken off and laidout in dottedlines. An adjustable weight, H, is employed, so that thegovernor can be set to hold the contactarms centrally at the normalspeed of the I110- tor to be regulated for its proper efficiency. Shoulda variation in the load cause the speed to slightly decrease, thegovernor-balls fall, and the arms make their lower contacts, closingcircuit to motor G, and causing it to revolve in a direction to shiftthe arm B to decrease the field strength, and so keep the speed at itsnormal point. When, on the contrary. the speed slightly increases,circuit is closed to the motor G in the opposite direction, and themovement of the arm B causes an increase in the field strength, whichkeeps the speed still at the normal.

It is evident that the field regulation hereinbefore described isapplicable to the field magnets of dynamo-electric generators, and alsothat the apparatus set forth may be used with series motors orgenerators when it is desired to throw their field-coils into or out ofmultiple-arc with one another.

WVhat I claim is- 1. The combination, with an electro dynamic motorhaving field magnet coils wound in sections, and in shunt relation tothe armature, of a commutator and connections, whereby the sections maybe progressively thrown into or out of multiple-arc relation with oneanother, substantially as set forth.

2. A field-magnet having two ranges of sectionally-wound coils, eachhaving one end connecting with the supplying-circuit, in combinationwith a commutator, connections from the bights of the sections tocontact-blocks of said commutator, and movable arms making contact withsaid blocks, and forming the free ends of the ranges, substantially asset forth.

3. The combination, with an electro-dynamic motor having its field-magnet wound in sections, of means for changing the relation betweenthe number of sections in series with the armature and the number inshunt relation thereto, and means for varying thestrength of thefield-magnet, substantially as set forth.

l. The combination, with a fieldmagnet having sectionally-wound coils,of the commutator consisting of the circular range of contact-blocks,the two contact-arcs, movable conductors connecting said arcs with saidblocks, and connections, such as shown and described, with the sectionsof field-magnet coils, substantially as set forth.

5. The combination of the circular range of contact-blocks, thecontact-arcs, and the pivoted arm consisting of an insulating center andmetallic extensions bearing on the arc and blocks, substantially as setforth.

6., The combination, with an electro-dynamic motor having itsfield-coils in sections and its armature in a shunt around a variablenumber thereof, of the commutator consisting of the circular range ofcontacts, the two arcs, the arm having metallic extensions bridging IIOthe arcs and contacts, the two arms bearing increased when the load isdecreased and de- 011 the contacts, and the armature and field creasedwhen the load is increased, to mainconnections, such as described andshown, tain a practically constant speed, substansubstantially as setforth. tially as set forth.

5 7. The combination, with an electro-dynam- This specification signedand witnessed this ic motor, of circuit-controlling devices for 21st dayof August, 1884:. varying the magnetizing effect of the fieldmagnetcoils, and apparatus connected with FRANK SPRAGUE' said motor, whosespeed varies with the load, WVitnesses: 10 and which affects saidcircuit-controlling de- WVM. H. 1VIEADO\VOROFT,

vices, whereby the said magnetizing effect is T. G. GREENE, Jr.

